Train board



Patented Feb. 2, 1932 STE PHEN YflT/ICGIFFERT, OF FORT SILL, OKLAHOMA, AND I-IUGH I; FORT SAM HOUSTON, TEXAS V I TRAINY-IBOABD Application filectMareh 9,1929. SerialNo. 345,717.

The resent a blicationrelates as indi- 'cated, to atrain board which may bedescribed as a device for instructing students inthe art of'con'ducting artillery fire. The

primary object of the inventionxis to provide,

a device of the class described which shall be of sufficient accuracy for training purposes without attempting to attain absolute" accuracybeyond'the appreciation of the average student. or instructor; one which shallbe small, easily d1smantled,l1ght in weight,

and quite inexpensive to manufacture; and one which shall be operable with a fair degree of accuracy 'byone not especially skilled "15 in artillery fire; Further objects of the invention will appear asthe description proceeds.

The present device which is known as a tram board ]S a portable terrain board, for

.. use in'the training of artillerists in thedes- '20 ignation of objectives, andinthe conduct of I artillery fire. It affords an opportunity, for

practice in handling the VZLI'iOHS'tYPQS of field artillery fire, without great expense, the expenditure of ammunition, and the assistance of several or more assistants and some elaborate and ilmnovable apparatus.

. It isa device which represents in'a greatly reduced scale aspecific area of ground and is provided with scales and other means so that,for any determined firing data the pro jectile falls at-approximately the same point onl'theg-round that it would fall in actual firing, or appears to bur-stat the same relae tive point in the air.

An advantageous feature of the device is that it is capable of representing the fire of a four-gun battery firing shellor shrapnehwith considerable speed. and accuracyin regard to, range, direction, distribution, and helght of burst. .Having the facilities to represent disprsion as well-as a visible difference to the student between a graze and an air burst, it

enablesthe student to simulate accurately and "frealistically; but on a miniature scale, the firing of an artillery battery under all conditions'and relative positions of target, battery,

andobservationpoint, which might arise on the target' ran ge orin actual-warfare; For example, problems may be fired involving the use of: eitherl direct or indirect aiming, time for representing the fire of a four-gun bat-" thereof taken from the right of Fig. .1 Fig."

or percussion projectiles, ranging orfir'e for [means constituting, however,,but one or va- "IIOUS mechanicalforms inwhich the principle :Of the invention may be used.

The. invention is' illustrated and described tery, but it will be apparent that by changing the number of appropriate elements it can'be used to represent the fire of other numbers of guns, or of tactical. units other'than'a bat tery.

In said annexed drawings: Fig. 1 .1s a plan view of a. tram board constructed in accordance with 'our'mvention set up for use; Fig. 2 1s. a front elevation 3 is a view similar to Fig. 2, the screen having been removed; Fig. 4 is a side elevation taken from the left of Fig. 3; Fig. 5 isalongitudinal section taken substantially. upon the line g 55 of Fig. 2; F ig.. 6 is a perspective view of a detail; Fig. 7 is a front elevationalview .of theburst slide;'Fig. S-isa plan view of the elements shown in Fig. 7; Fig. 9 is. a side elevation of the burst slide .taken, from the right of Fig. 7; Fig. 10 is a longitudinal section taken substantially 'on the line 10-10 of Fig. 7 Fig. 11 is'anenlarged viewof the scale on the range arm; Figi'12 is a-front eleva-tional view of a modified form of burst slide; Fig. 13 is a side elevation thereofta'ken from'the left of Fig. 12; Fig. 14 is a plan view thereof; F ig'. 15 is a transverse section taken substantially upon the. line 15'15 f0f Fig. '13; :and Figrltl is a fragmentary sectional view of a modification of :31 detail.

Referring more particularly to the drawings, the reference numeral indicates the train board generally, the same comprising a floor 21 printed or painted to represent the terrain, side walls 22, and a back wall 23 printed or painted to represent a horizon panorama. A pair of range arms 24 are shown supported upon the side walls 22 and rear wall 23, but they may be supported in any desired way. Said arms extend forwardly beyond the ends of the side walls 22 and substantially to the end of the floor 21, the arms being substantially parallel throughout their lengths. A screen 25 is formed with side flanges 26 which constitute bracing wings, and said screen is adapted to stand before the open end of the terrain, the ends of the flanges 26 being slightly spaced from the adjacent end of the terrain. Said screen is further provided with a bottom wall 115 extending between said wings 26. The inner end of said bottom wall is formed, as shown, as an arc of a circle, the center of which is disposed approximately in the mid dle of the terrain. The forward end of the floor 21 is finished in a convex arc 21 bearing against the concave are of the member 11.5. Said end of the wall 115 is marked, as shown, with graduations 116, whereby, when the terrain is moved with respect to the shield in horizontal plane, the corners of the terrain will cooperate with the graduations to indicate to the operator the angles 4; i. e., the observer-targetgun angle. The shield is further formed with a cut-away portion at its lower end to provide a sighting space or aperture 27 through which the student is afforded a view of the terrain. A deflection indicator 28, which is preferably transparent, is mounted in a slot in the floor 21 for lateral movement with respect to the terrain. (See Figs. 1, 2 and 5.)

A pair of shoes 29 formed with convex lower surfaces 30 (see Figs. 4 and 6) are secured to opposite ends of a graduated cross bar 31, said shoes being adapted to be mounted upon the upper surfaces of the range arms 24. The cross-bar 31 is formed with a slot 32 extending substantially from end to end thereof, and a sheaf block 33, the function of which is explained hereinafter, is mounted on said bar through the medium of a pair of screws or rods 34 extending through said slot 32. As is clearly shown in Figs. 1 and 8, the sheaf block is provided with a plurality of strings or wires 35 arranged on its upper surface in parallelism, and a bead 36 is slidably mounted upon each of said members 35. Of course it is to be understood that we may modify this structure by providing guides of different kinds in place of the strings 35 and different movable members in place of the beads 36. One string 35 and bead 36 is provided for each gun the fire of which is to be represented.

Straddling the cross-bar 31 and mounted between the members 34 is a burst slide 37 slidable on said bar 31 (see Fig. 10). In its one face, preferably that face adjacent the sheaf block 33, said slide is formed with a vertical slot 38 in the lower end of which there is secured a sleeve 39. A wire 40 is threaded through said sleeve and is mounted in said slot, said wire being bent at its upper end to provide a hook adapted to be hooked over the upper end of the slide 37 to retain the wire in its uppermost position. At the extremity of said hook portion there is mounted on the wire a bead 41, and at the lower end of said wire there is mounted a similar head 42. The bead 42, and preferably the bead 41, are formed of glass or other translucent material colored in any manner well known to the art. Preferably the bead 42 is black or dark, to simulate the color of a graze burst of an artillery projectile, and the bead 41 is of the same color.

In the opposite face of the slide 37 there is formed a second vertical groove 43 in the lower end of which is secured a tube 44. A wire is threaded through said tube 44 and lies in the groove 43, the upper end of said wire being bent as is the upper end of the wire 40. A bead 46 is secured to the upper end of the wire 45 and a head 47 is secured to the lower end thereof. These beads 46 and 47 are similar to the beads 41 and 42 in every way except that the beads 46 and 47 are light in color, preferably smoke gray, to simulate the appearance of an air burst of an artillery projectile. While we have shown the beads 42 and 47 as spherical, it is to be understood that we may use beads of irregular outline intended to simulate more closely the appearance of a cloud of smoke from a bursting projectile.

Referring now to Fig. 7, it will be seen that a quadrant 48 is pivotally secured as at 49 to that face of the slide 37 in which is formed the groove 43. Said quadrant is formed on its one edge with a plurality of numbered notches 50, adapted to stop the hooked upper end of the wire 45 at various heights, thus, when the wire is dropped, holding the bead 47 at a height above the terrain corresponding to the notch set opposite the groove 43. The respective notches may conveniently be marked according to the height in mils above the terrain at which each will hold the bead 47 and at its free end, said quadrant is formed with a pair of ears 51 and 52 adapted to engage, at the limits of motion of said quadrant, with a stop 53 on the slide 37.

The sheaf block 33 carries on its upper surface beneath the members 35 a scale 54 which is graduated, as indicated, for deflection. In the use of the device, the beads 36 are set in relation to this scale in response to the orders of the person conducting fire.

On its one edge, the slide 37 carries a scale v55. which isgraduated: to indicate the height. V a of burst of proj ectiles thrown from the hypo-1 i thetical; guns. Mountedadj acentthis scale. s

on theislide' 37 there is a string-ior wire 56 uuponwhich is-slidably carried a bead 57 i .The scale 555 comprises also a-ratio table 58.

:.-:W.l1i(2hi indicates, fona ny, given setting of the bead 57 the ratio of lfair bursts-= to raze bursts? which are to be indicated byathe op:

-ierator in: responding 1, to the orders of the aperson conducting fire.

7; As a anodification of the. above described 1arrangement,vtheslide1;;37 maybe -bored respectively of; the-scale J55, and a string or :the face of the 'slideg37 to prevent accidental movement-10f said bead.

,As is -clearly: shown in Figs.- 5 and 11,the mange-arms; 24 carry. identical scales 59:

pends from saidlkey 79 between the bar 31 .iwgraduatedto indicate :range setting of the ;,-piece. In-carrying on a problem of fire, the :-=operator :sets each shoe 29 at a given point :on. its respective: scale-59in response to the morder :of: the person conducting: fire, it being* munderstood that the two shoes29 are always s set on identical points on the respective scales 1 a As is shown i'nFig; 6,.each of said shoes .i29-comprises a substantially triangular web 60 backed by a block 61 substantially'midway HbGiSWQBI I the ends-of said shoe,

of, said shoe-is, as shown, somewhat thicker lat its mid portion-63 than at its end portions 6 1, thus giving convexity to the lower surface of said flange which is adapted to' rest upon Lwthearange arm 24. lirorder to preventslipi-pageea-ndi to assure anamtenance of :a given settingof the shoes, friction means are providedbetween the shoes and; the range arms.

- In the;presentapplication,we have illustratedithis friction .meansas a rubber band 165 stretched aroundthe shoe, lying flat upon the surface 30 and tensioned over the: upper vendofthe block '61, -However,it isito be understoodthat-ave. do not intend to limit'y registering W'ith'thebore of'the neck86, 87

ourselves to this exactfstructure, but that we may use a piece of friction materialcemented orotherwise secured to the: surface 30 or piece'of friction material cementedor 'other "wise secured tethe upper surface of each of the range arms 24. r

"WVhilethe above described burst slide is inga bifurcated base comprising-- legs 67 adapted to straddle the crossbar 31,:and

"'formed to receive securing element-"68' 1 passing below-said bar. f At 1' its upper end;

T he flange- 62 thesIide-iS formedwith a pair of lateral projections69and at its lower end, the same is provided with another pair of projections 70. A==rod7 1- isrsecuredin apertures in one pair ofa rojections 69," 70 adjacent one side of the slide, I and in: vthe other projections 69 :and '70 there is secured a similar rod72 adv jacent the opposite side of the slide 66.

. A handle member 7 3 is formed adjacent its one end with a collar 74 and a collar 75,-the r collar 7 1 being formed With a-bore'76'and the collar 7 5 with a" bore 77; in alignment with L the bore 76. The collars 74s and 75are spaced :apart by azrslot 78 formed in the handle memher on a plane substantiallyperpendicular tothebores 76 and 7 7' and the collars =74 and 7 5. may be, andshereinafter 'are, considered 1 together as a neck. In assembling the device, the rod 71 isithreaded through the bore 77 of the collar 75', through an aperture '82 in a keyi79 mounted in the slot 78, andthrough thebore 1'76, thus mounting the handle member 73and. the key 79 slidablyon said rod. Said key 79 is formed with anupturned'end 8O towhichis secured in any desiredrnanner :tlreupperend :of a Wire 81. Said Wire deend a bead '81 similar to the bead 4L7.

As has been stated, the key/T9- is formed 'with an aperture SQ-Which, in the assembled device, is alignedwiththebore 76 and 77 and isthreaded'on the rod 71. Saidzkey is bifurcated-at its'end opposite the end 80,:and :the furcations 83stliereof, when the'device is assembled, lie on opposite sides of the edge a=:flange 84' forming a part'of the burst slide-"66. Thus it will be-seen, that the A similar handle member 85 is formed with a neck-'86, 87 slotted as at 88 forthe *lCCQPlJlOll-Of a 'key 89 having an upturned outerend 89": to whichis secured a wire 90 similar to the wire 81. A bead 90 similar to" the bead l2 iscarried'atothe free end of thewvire 90. As isclearly shown in Fig=. 15,

the key -SQ -is formed' with. an aperture 91 and threaded on therodf72,a11d said key is '93-sin iilar to the flange 84. The. handle 85 bis: thus 1 slidably and oscillably mounted on the rod 72 and the-key S9 is slidable on said rod but isheld by the furcations .92 and the flange 93'against oscillation Withthe handle member 85.

f'iAdjacent its upper end, the burst slide 66 is -formed with a'pair 10f laterally projecting lugs 96, I97. --VVhen the: handle 73- is elevated to its upper-extreme and; is rotated into: the

:and the projection 70 and has secured to its position shown in Figs. 12 to 15, the lug 96 cooperates with said handle to prevent the same from sliding downwardly on the rod 71, and the lug 97 performs the same function with respect to the handle member 85.

011 the side of the burst slide 66 adjacent the rod 71, there is mounted a quadrant 98 formed in its one edge with a plurality of notches 99 and pivoted as at 100 for swinging in a plane parallel to said side of the burst slide. At its upper end beyond said pivot, said quadrant is formed with a lug 101 which is adapted to cooperate with a stop 102 on said slide to limit the swinging movement of the quadrant.

In using the above described device, the train board is set up on a table, with the screen in the position illustrated in Figs. 1 and 2. The battery position is assumed at a point removed an arbitrary distance from the board on a line normal to the center of the terrain. For a number of problems, of course, this line is also normal to the center of the sighting opening in the screen 25, but, where problems of lire conduct from a forward and laterally removed observation post are to be presented, the terrain is rotated to provide for different desired observer displacements from the line of fire. Consequently, the terrain is preferably mounted upon a frame or platform (not shown) providing a support for the terrain, it being understood that the terrain is adapted to be moved without any consequent movement of the sighting screen. The person who is to conduct the fire seats himself a given distance from the front end of the board with his eye substantially on the level of the upper edge of the sighting aperture. A target is placed on the terrain, said target comprising, for instance, four burned match heads or beads, or other small objects. The deflection indicator 28 is then moved in its slot until the center line thereof comes into line between the eye of the student and the target which he selects to be fired upon.

in the use of a board of such small dimensions as the one contemplated by the present invention, the phenomenon of parallax causes a relatively large apparent lateral deviation of a shot as a result of a very slight movement of the students head. tis therefore i mportant to fix the position of the observers eye when observing fire, inasmuch as a slight movement of the head might have the same effect on the terrain as would a movement of several hundred ya d of the observation post in actual practice. here a target on the terrain is in use, the correct position of the observers eye is, of course, fixed after the scale 28 has once been located with respect to the target. When, however, high burst range problems are being presented, the target is not in view of the observer, and consequently means must be provided for establishing the proper position of the observers eye. This response to this command.

may be accon'iplished by providing a stand comprising a vertical wire carrying a bead, and the line of sight may be established by the operator, by placing the stand in a position to be seen by the observer as he sights across or through the scale 28. Such a stand is shown at 28, Figs. 1, 2 and 5, the bead being designated 28 The student then gives the commands necessary for opening fire. For instance, the student may say Aiming point, blockhouse on Signal Mountain. This is an imaginary point, and the student gives this command only because it is the usual opening command in field firing. The operator does nothing in The next command of the student is Deflection, Plateau four, Drum 150. This is an arbitrary deflection announced by the student merely as a basis from which to work in adjusting upon the target. In response to this command, the operator assumes that the specified deflection measured from the announced aiming point Will place the center of the batterys fire in a lateral position on the cross-bar arbitrarily selected. In practice, there is always some error in the initial deflection setting, and this must be corrected in subsequent firing after noting the effect of the first shots. The students next command is On No. 2, Open This command determines the Width of the sheaf to be fired by the battery. This command takes No. 2 piece as being on its portion of the target, and the previously announced deflection is to be assumed, in response to this command, by No. 2 piece. No. 1 piece assumes a deflection 10 mils to the right of the announced deflection, No. 3 assumes a deflection 10 mils to the left thereof, and No. 4 piece assumes a deflection mils to the left thereof. Such a wide sheaf is necessary in practice in order to separate the fire of one gun from that of another at the beginning of fire sufficiently so that the fire of each piece may be individually identified and placed upon its proper part of the target. In the operation of the train board, the operator responds to this command by setting the bead 36 representing No. 2 piece at an arbitrary position, setting the bead 36 representing No. 1 piece at a position 10 mils to the right thereof, that representing N0. 3 piece at a point 10 mils to the left thereof, and that representing No. a piece at a point 20 mils to the left thereof. The students next command is Site, plus ten. This command is given on the assumption by the student that the target is at an elevation above the horizontal plane of the gun emplacement corresponding to an angle-of-site setting of 10 mils, and the operator does nothing in re sponse to this command. The student then announces Shrapnel as the type of ammunition to be used, Corrector indicating the settingofthe'time fuse of the shell which is to be used, Battery'Salvo Right, 3400.

Temperature and other climatic conditions-- have a considerable effect upon the location ferent climatic conditions, the same corrector settingmay result in'--graze bursts"-.'- (lense quently,j-in response to the order-Corrector 30?, the operator assumes an arbitrary height of burst andsets the bead 57" at this height Thesett-ing of this head then is changed with each announcement of the change in the cor-'- rector-setting or the setting of the-angle of site. V

Tlie 1 command Battery Salvo Right in dicates that 1111- tour guns of the battery are 1) is to-firefirst. The-command 3400'indi-i cates' th'at theran-geiat which the battery is to befired-is 3400 y-ards, andafter the range is given;'tlie' guns 'are fired as soon as 'th'e'set' tings are completed. In response to this command, the'operatorsets the two shoes 29 at the indicatedpoints corresponding to 3400 30 yards on-the-range arms 24.

The various settings "having been completed in complia'ncewith the students com-' mands, the operator calls out the'way and,-liriing the wire 40withthebead 36rep-- resenting-No; 1 piece,- releases one of the'wires 40 'or45 'and'permits the bead 42 or 47*to drop into the view of'the student through the sightp y 7 A v the-sheaf block 33 is moved-bodily along the ing aperture 27, representing the bal]. of smoke iota shrapnel burst from No; 1 piece; 40 about the duration o fsuch an actual smoke ball, the beadiswithdrawn andthe wire is hookedin placeonce more. Suppose that the operatorhas assumed-a height of burst-of 'plus threemils; By referring to the table 58,

the*operator-csees that, in a salvo of eight shots, this setting will result in 'seven air bursts and one graze burst." If, only one" round from each piece is to be fired, the oper ator-willprobably'drop'thebead 4740i each shot',thusindicatingfour air bursts,= it being understood-that the quadrant-48 has beenset' so that the notch 50 numbered 3,,will intercept-the handle portion'of the wire'45 when the same is dropped, thus stopping the-bead 47 a height of '3 mils abovethe terrain21. Aftenthe first shot has been'indicated, the operator moves the burst slide untilthe wire 40"is aligned- 'withthe bead 36 which repre and pulls it .up again after t a two. or three second interval, repeating theloperation with the wire 40 in alignment with each of the fire two salvos, the operator will drop the I or the other of the beads, he almost unavoid-" to be-fired that theyareto befiredby salvo, thatis,-in regularorder at intervals of-thr'ee' seconds, and that the" right-hand piece (No;

'Af-ter "not -more than-two or three seconds,-

sents No; 2 pieceand again 'drops"ithe bead47 that of the cross ba'r beads 536-,successiv'ely; If theibattery is to A N p Y Qlhy' means ota strlng passed through eyes bead 42once during eight shotsentirely" down to the terrain 21 to-indicate-a graze-burst,

-there'being nothing on-the front-sideof the slide 37- to stop'the wire40i Thetable 58 is based upon "experience andthelaw of Q probabilities inview of variations in=a1nmu-**- nition, and this table is suiiiciently accurate for practice-work. V I

Such variations 1n ammun tion-alsoresult in differences inthe distanceto which various other; Obviously; "such-rocking, causes the shots to be indicated at different pointsfrela tive'tothe'ran'geset; some-at a slightlygreate er and someat a slightly shorter ranger After-the student-has noted the results fromreo.

the settings which he has specified',- hecoIn-E" mands such changes In zthe settings "asf'seern to hnn to be necessary"inorderto br1ng the*'-* fire of thebattery'to bear dir ect'lyon the tariget, and his commands are's carriednout Joy-' the operator by, movements of the shoes 29, the sheaf block 33', the'slid'e 37;"and the quad-- rant 48. The student continues to correct the settings until finallyithe batery is brought to bear directly uponhis target. I

.As{ will fhe' "obvious, when itis desired to change the direction of the batterya's a wholg? cross-ba r31, wh'ereas; i'f-it is desired to changethedirection-only ot-individual pieces; the i respective beads- 36 are moved on their wires As 11 as-been stated, l the whole trai'n --'board'- o is easily 'disma-ntled for 'transportationfand another advantage of this arrangement 'lies 1 in the fact'that diifeientsetsof range arms? may-be s'uppliedwith 'eachboard=,- -and= these sets may' besubstituted-for eachpther iin order to simulate "the-fire of guns of diiferent 'typesandtheuse of ammunition of-difierenfi 'typesw Thescaleson'th'e range'arms maybe made a removable as an 1 alternative tofthe above arrangement, or different scales may be -marked on the samesetof range arms as 'shownin Fig. 11; Preferably, light' bullo's are supported; frem the rear wall 23 of the boards abovet'he level of the sighting aperture27';

or on the inner surface and adj acen't the op posite sides of the screen 25 level below 'lliroughfthe use of hooks suspende d from.

the rangearms," suspended 'ftarget work'may be simulated, andinovingt'argetrwork maybe simulated by drawing target across'thefloor (not shown) mounted on the floor. Of course it will be understood that the same head which indicates a graze shrapnel burst will also indicate a percussion shell burst; and

that the same bead which indicates an air identical to that above described, but the "latter slide is much more substantial.

The arrangement of rods 71, 72, handles 78, 85, and keys T9, 89 removes all possibility of bending of the wires 81 and 90 through rough .usage of the handles 73 and 85, since said "handles are not directly connected to the wires and any shoeh's sustained by the handles will be transmitted only to the rods 71 and 72.

. Other modes of. applying the principle of our invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated meansbe employed.

We therefore particularly point out and distinctly claim as our invention:

1. In a device for giving instruction in the conduct of artillery fire, means representing a terrain, graduated scales associated with said means,an element movable with respect to said scales in response to commands from a student, means screening from the students .CTI

. sight said scale and said element but permitconduct of artillery fire, means representing a terrain, graouated scales associated with said means,an elementmovable with respect to said scales inresponse to commands from a student, means screening from the students sight said scales and said element but permitting a view of theterrain, and means carried by said element. and projcctible into the view of the student for momentarily representing projectile bursts relative to the terrain, said last-mentioned means including separate elements for representing respectively air-bursts and graze-bursts.

i. In a device for giving instruction in the conduct of artillery fire, a frame comprising a. base, side and rear walls secured to said base, a pair of arms secured to said side and rear walls and'extending forwardly therefrom, said arms being graduated to indicate range and corresponding elevations from a given hypothetical gun placement, and a sighting screen movable with respect to said base into a position either in prolongation of the space between said arms or to the side thereof.

5. In a device for giving instruction in the conduct of artillery lire, a frame comprising a base,side and rear walls secured to said base, said side walls extending to a point short of the front end of said base, and a screen adapted to be moved horizontally independently of said frame, said screen being adapted to mask the upper portion of said frame.

6. Ina knock-down device for giving instruction in the conduct of artillery fire, a frame comprising a base, side and rear walls detachably secured to said base, a pair of arms detachably secured to said side and rear Walls and extending forwardly therefrom, and a sighting screen movable with respect to said. base into a position either in prolongation of the space between said arms or to the side thereof.

.bar,.a shoe mounted on each end of said cross-bar, said shoes being, slidably mounted on said arms, and a sighting screen movable with respect to said base into aposit-ion either in prolongation of the space between said arms or to the side thereof.

8. In a device for giving instruction in the conduct of artillery fire, in combination with means representing a terrain and including.

a pair of parallel range arms, means mounted onsaid arms comprising a cross-bar and a shoe having a convex bottom surface mounted on each end of said crossbar said shoes having their convex surfaces slidably mounted in said arms, respectively.

9. In a device for giving instruction in the conduct of artillery lire, in combination with means representing a terrain and including a pair-of parallel range arms, means mounted on said arms comprising a crossbar, a shoe having a convex bottom surface mounted on each end of said cross-bar, said shoes having their convex surfaces slidably mounted on said arms, respectively, and friction means between said arms and said respective shoes.

10. Ina levice for giving instruction in the conduct of" artillery fire, in'combination with means representing a terrain and including a pair of parallel range arms means mounted on said arms comprising a cross-bar, a shoe having a convex bottom surface mounted on each end of said cross-bar said shoes having equal convex surfaces slidably mounted on "of said vwires.

said arms, respectively; and a friction member mounted on the convex surface ofeach of said shoes.

11. In a device forgiving instruction in 5 the conduct of artillery fire in combination with means representing a terrain a crossbar movably suspended adj acentsaid means, a member slidably mounted upon said cross bar, a pair of elements suspended fromsaid n'ieinber and vertically reciprocable with res iect thereto, and means adapted to suspend. 7

said elements above the terrain and adapted, when released, to permit said elements to fall into close proximlty with the terrain.

12-111 a device forgivinginstruction in the conduct of artillery fire, in combination with means representing a terrain, a crossiar movably suspendedadj acent said means, a member slidably mounted upon said cross- 2@ "bar, a pair of Wiressuspended from said member andvertically reciprocable with respect thereto,,a bead mounted at the lower end or one of said wires, and ahead of different appearance mounted at one endo'f the other 1 3..Ina device for giving instruction in the conduct of artillery'fire, in combination with means representing a terrain, a crossbar movably suspended adjacent said means,

39 a. memberslidably mounted upon said crossbar, anelement simulating'the burst of a projectile-suspended from said member and vertically reciprocable with respect thereto, said element; being adapted to be dropped into, predetermined proximity with the terrain, and means to limit the length of drop of said element. v

14. In a. device forgiving instruction in the conduct of artillery fire, in combination with means representing a terrain,- a cross bar movably suspended adjacent said means, a member slidably-mounted upon said crossbar, an element suspended from said member and verticallyreciprocable with respect thereto, said elementbeing projectible downward into proximity with the terrain, and iiieans-,=adjustable before the movement of saidelement to limit, in varying degrees, the degree of downward projection of said ele- 'ment; V

15. In-a device .for giving instruction in the-conduct of-artillery fire, in combination with means representing a'terrain, a cross-. bar movably suspended adjacent Silld'Il'lQflIlS, a member slidably mounted uponsaid cross bar, an element suspended from said member and vertically reci'procable with respect thereto, said element being projectible int-o proximity with the terrain, and means pivotedto said member and swingable t0 limit, in varying degrees, the degree of projection of said element. c

16: In a deVice-J-for giving instruction in the-conductof artillery fire, in combination with meansrepresentinga terrain, a cross-bar i operator the proper movably suspended adjacent saidmeans, amember slidably mounted upon said crossbar, an element suspended from said member and vertically reciprocable with respect thereto, said element being projectible into proximity with the terrain, and a notched quadrant pivoted to said member and swingable to project into the path. of said element to limit, in varying degrees, the degree of projection of said element.

17. In device for gi the conduct of artillery fire, in combination with. means representing a terrain, a graduated'cross-arm movably suspended adjacent said'means, a slide on said cross-bar, a sheafblock slidably mounted on said cross-bar, a scale onsaid block, .a' plurality of parallel members longitudinally mounted on said block adjacent saidscale, an element slidable oneach of said members to represent a specific piece of a battery, said slide being movable into registry with-any one of said elements, and means suspended from said slide and projectible into close proximity with the terrain.

18. In. a device for giving instructionin.

the conduct of artillery fire, in conibination with means representing a terrain, a-

graduated cross-bar movably suspended adjaeent said means, a slide on said cross-.

ving instruction in endof the other of said wires adapted to be tioned bead, when dropped, above the tier ra1n.i

dropped toward the. terrain, and means on said slidead ustable to stop sa1d last-men- 19. Ina device for giving instruction in the conduct ofartilleryfire, means represent ing a ter ain, a member movable by an operator relative to said terrain'in response to" a student?s orders means carried by said member for indicating graze bursts relative" to the terrain,'means carried by said member for indicating air bursts relative to the terrain, and/means for indicating to'the ratio of air bursts to graze bursts? for any given height of burst 7 setting.

' 20. In a devicejfor giving instruction inv the conduct of artillery fire,means representing a terrain, a member movable by an op-- erator relative to: saidterrain in response to a students commands, means carried by said member for indicating graze-bursts,

relative to the terrain, means carried by said member for indicating air-bursts relative to the terrain, and means carried by said member and adjustable by the operator in response to a command of the student for indicating to the operator the proper ratio of air-bursts to graze-bursts for the specified setting of the piece.

21. In a device for givinginstructioninthe conduct of artillery fire, means representing a terrain, a member movable by an operator relative tosaid terrain in response to a students con'nnands, means carried by said member for indicating graze-bursts relative to the terrain, means carried by said member for indicating air-bursts relative to the terrain, a scale carried by said member, an element mounted on said member and extending longitudinally of said scale, and means slidable on said element by the operator in response to a command of the student for indicating to the operator the proper ratio of air-bursts to graze-bursts for the specified setting of the piece.

22. In adevice for giving instruction in the conduct of artillery fire, a bar, a slide having a bifurcated base adapted slidably to receive said bar, a rod mounted on said slide, a handle member slidable on said rod, a wire suspended from said handle member, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move said wire to position said simulating means in given relation to said slide and said rod.

23. In a device for giving instruction in the conduct of artillery fire, a bar, a slide having a. bifurcated base adapted slidably to receive a bar, a rod mounted on said slide, a handle member slidably and oscillably mounted on said rod, means slidable with said handle member but held against oscillation therewith, a wire secured to said means, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move said wire to position said simulating means in given relation to said slide and said rod.

2st. In a device for giving instruction in the conduct of artillery fire, a bar, a slide having a bifurcated base adapted slidably to receive said bar, a rod mounted on said slide, handle member comprising a bored neck slidably and oscillably mount-ed on said rod, said neck being formed with aslot in a plane perpendicular to the bore thereof, a key re ceived in said slot and slidably mounted on said rod, and a wire secured to said key, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move said wire to position said simulating means in given relation to said slide and said rod.

25. In a device for giving instruction in the conduct of artillery fire, a bar, a slide having a bifurcated base adapted slidably to receive said bar, a red mounted on said slide, a handle member comprising a bored neck slidably and oscillably mounted on said rod, said neck being formed with a slot in a plane perpendicular to the bore thereof, a key received in said slot and slidably mounted on said rod, said key being formed with an aperture adapted to register with said neck bore and to be threaded on said rod, means to prevent oscillation of said key, a wire secured to said key, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move said wire to position said simulating means in given relation to said slide and said rod.

26. In a device for giving instruction in the conduct of artillery fire, a bar, a slide formed with apair of parallel flanges and adapted to be mounted on a bar, a rod mounted on said slide in the plane of each of said flanges, a handle member comprising a bored neck slidably received on each of said rods, each of said necks being formed with aslot in a plane perpendinclar to the bore thereof, a. key received in each of said slots, each of said keys being bifurcated at its one end and formed with an aperture intermediate its ends adapted to be threaded on its respective rod, the furoations of each of said keys lying on opposite sides of its respective flange, a wire secured to the opposite end of one of said keys, a bead on the free end of said wire, a wire secured to the opposite end of the other of said keys, and a bead of different appearance on the free end of said second wire.

27. In a device for giving instruction in the conduct of artillery fire, a bar, a slide adapted to be mounted on said bar, a rod mounted on said slide, handle member slidably and oscillably mounted on said rod, means slidable with said handle member but held against oscillation therewith, a wire secured to said means, means on said slide for suspending said handle member adjacent the top of said rod, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move saide wire to position said simulating means in given relation to said slide and said rod.

28. In a device for giving instruction in the conduct of. artillery fire, a bar, a slide adapted to be mounted on said bar, a rod mounted on said slide adjacent one side thereof, a handle member slidably and oscillably mounted on said rod, means slidable with said handle member but held against oscillation therewith, a wire secured to said means, a lug on the same side of said slide and positioned to engage said handle member in one rotative position of the latter to suspend the same adjacent the top of said rod, and means on the same side of said slide adapted to be positioned in the path of said handle mem her in another rotative position of the latter for limiting the downward sliding movement of said handle member, and means carried by said wire simulating the appearance of the burst of an artillery projectile, said handle being adapted to move said wire toposition said simulating means in given relation to said slide and said rod.

29. In a device for giving instruction in the conduct of artillery fire, a bar, a slide adapted to be mounted on said bar, a rod mounted on said slide adjacent one side thereof, a handle member slidably and oscillably mounted on said rod, means slidable with said handle member but held against oscillation therewith, a Wire secured to said means, and means on the same side of said slide adapted to be adjustably positioned in the path of said handle member variably to limit its sliding movement downwardly.

30. In a device for giving instruction in the conduct of artillery fire, a slide, a rod mounted on said slide adjacent one side thereof, a handle member slidably and oscillably mounted on said rod, means slidable with said handle member butheld against oscillation therewith, a wire secured to said means, a bead on the free end of said wire, a lug on the same side of said slide and cooperable with said handle member, in one rotative position of the latter, to hold the same adjacent the top of said rod, a second rod mounted on said slide adjacent the opposite side thereof, a handle member slidably and oscillably mounted on said second rod, means slidable with said handle member but held against oscillation therewith, a second wire secured to said last-mentioned means, a. bead of different appearance on the free end of said second wire, and a lug on said opposite side of said slide and cooperable with said last-mentioned handle-member, in one rotative position of the latter, to hold the same adjacent the top of said second rod.

31. In a device for giving instruction in the conduct of artillery fire, a slide, a rod mounted on said slide adjacent one side thereof, a handle member slidably and oscillably mounted on said rod, means slidable with said handle member but held against oscillation therewith, a wire secured to said means, a bead on the free end of said wire, a lug on the same side of said slide and cooperable with said handle member, in one rotative position of the latter, to hold the same adjacent the top of said rod, a second rod mounted on said slide adjacent the opposite side thereof, a handle member slidably and oscillably mounted on said second rod, means slidable with said handle member but held against oscillation therewith, a second wire secured to said last-mentioned means, a bead of different appearance on the free end of said position of "the latter, cent thetoppi-said rod,-a second rodmounted "on said slide adjacent the opposite side there-- "second wire,a lugon said opposite side of said slide and cooperable with'said last-mentioned handle-member, in one rotative positionofthe latter, to hold the same adj acent the-top ofsaid: second rod, and means to limit downward movement of said :second handle member.

32. In a device for giving instruction in the conduct "of artillery fire, a slide, a rod mounted on said slide adjacent one sidethereof, a handle member slidably and oscillably mounted onsaid rod, means slidable with said Handle member but held against oscillation therewith. a wire secured to said means, a

head on the :t'ree'e'n'd of said wire, a lug on the same side of said slide and cooperable with said handle member, in one rotative to hold the same adjaof ,a ha nd-le member slidably and oscillably mounted on said second rod, means. slidable with said handle member but held against oscillation therewith, a second wire secured to -sagid-last-ment'oned means, a head of dif ferent appearance on the free'end'of said second wire, a lug on said opposite side of said slide and cooperable with said last-mentioned handle-member, in one rotative position of the latter, to hold the same adjacent the top of said second rod, and a quadrant pivoted to said opposite side of said slide, said quadrant being formed with a series of notches in its edge adjacent said second rod, and being swingable to bring such notches selectively into the path of said second handle member when the latter is in another rotative position.

33. In a device for giving instruction in the conduct of artillery fire, means representing said means between said means and the students eye, said screen being formed with a sighting aperture, and transparent movable means associated with said aperture and carrying indicia adapted to indicate to the student lateral displacement of objects on the terrain from his line of sight.

35. In a device for giving instruction in the conduct of artillery fire, meansrepresenting a terrain, a screen intercepting the students vision of said means, said screen being formed with a sighting aperature through which said means are visible in perspective,

and a transparent scale mounted to slide transversely in said aperture.

36. In a device for giving instruction in the conduct of artillery fire, means represent ing a terrain, and an upstanding screen adj acent an edge of said means but movable independently thereof, said screen being formed with a sighting aperture adapted to permit vision therethrough along said means.

37. In a device for giving instruction in the conduct of artillery fire, means representing a terrain, said means being mounted for movement in a horizontal plane, a screen adapted to be stationarily mounted upstanding adjacent an edge of said means, said screen being formed with a transverse sight ing aperture at the approximate level of said means, and a scale on said screen cooperable with the adjacent end of said means for indicating to an operator the observertarget-gun angle.

Signed by us this 15th day of February, 1929.

STEPHEN Y. MOGIFFERT. HUGH P. ADAMS. 

